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Title: Threshold photoelectron spectroscopy of unstable N-containing compounds: Resolution of ΔK subbands in HNCO{sup +} and vibrational resolution in NCO{sup +}

The threshold photoelectron spectra (TPES) of two unstable nitrogen-containing species, HNCO and NCO, were recorded utilizing vacuum ultraviolet synchrotron radiation. Both are intermediates in combustion processes and play a role in the removal of nitrogen oxides from exhaust gases. The rovibronic structure of the first band in the TPES of HNCO{sup +} was analyzed within the framework of an orbital ionization model, and the resolved structure of the origin band was assigned to ΔK subbands. An ionization energy of 11.602 ± 0.005 eV was determined and the vibrational structure of the cationic ground state was analyzed by a Franck-Condon fit. Low lying electronically excited states of HNCO{sup +} were also observed. In a second series of experiments, the NCO radical was generated by flash pyrolysis from chlorine isocyanate. The ionization energy to the X{sup +} {sup 3}Σ{sup −} ground state was determined to be 11.76 ± 0.02 eV, while for the a{sup +1}Δ state, a value of 12.93 ± 0.02 eV was obtained. Vibrational structure was observed for both states, and bands were assigned by Franck-Condon simulations.
Authors:
; ;  [1] ;  [2] ; ; ;  [3] ;  [4]
  1. Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg (Germany)
  2. Synchrotron SOLEIL, l’Orme des Merisiers, Saint Aubin BP 48, F-91192 Gif sur Yvette Cedex (France)
  3. Laboratoire de Chimie-Physique, UMR 8000 CNRS and Université Paris-Sud 11, F-91405 Orsay Cedex (France)
  4. Molecular Dynamics Group, Paul Scherrer Institute (PSI), CH-5232 Villigen (Switzerland)
Publication Date:
OSTI Identifier:
22415769
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 18; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CHLORINE; COMPUTERIZED SIMULATION; EV RANGE; EXCITED STATES; EXHAUST GASES; FRANCK-CONDON PRINCIPLE; GROUND STATES; ISOCYANATES; NITROGEN OXIDES; PHOTOELECTRON SPECTROSCOPY; PYROLYSIS; RADICALS; RESOLUTION; SYNCHROTRON RADIATION; ULTRAVIOLET RADIATION